How to get a single input property of a node to draw in the UI panel directly in the panel?
UILayout.prop index argument

Use the index property for single array elements.

layout.prop(map.inputs[1], "default_value", text="Position X", index=0)


Would point out that this is used in my answer https://blender.stackexchange.com/a/139620/15543 to link posted in your question?

FWIW. For pep8 formatting put a space after a comma in arguments list.

It is recommended in blender to use double quotes for strings, and single quotes for enums.